Attachment-plug



B. JQGRIGSBY.

ATTACHMENT PLUG.

APPLTCATION FILED JAN. 12. I918.

Patented Nov. 29, 1921..

2 SHEETSSHEET 1 B. J. GRIGSBY.

ATTACHMENT PLUG.-

APPLICATION FILED JAN-12,1918.

2 SHEETS- T2.

ggg Patented Nov. 1921.

the cord or its I described in the specification, -80

- in modifications.

E STATES 'PATET oi.

BERTRAM d. GRIGSBY, OF CHICAGO, ILLINOIS.

ATTACHMENT-PLUG.

messes.

Specification of Letters Patent.

Patented Nov. as. near.

Application field January 12, 1918. Serial No. 211,530.

This invention relates'to plug attachments for electrical devices, and the object of the invention is to provide-a reliable conductor cord gripping means for connecting the conductor cord to the plug in such a way as $0 avoid objectionable kinking of the. conductor cord at its point of attachment to the plug, and also to avoid transmitting stress, I

due to a pull on the cord, to the terminals or binding screws of the plug. Another object of the invention is to avoid breaking envelop bybending it sharply over the plug at the point where thecord emerges from said plug. 1

The invention consists in the combination and arrangement shown in the drawings and and is pointed out in the appended claims.

As shown in the drawings:

Figure 1 illustrates the use of my conductor and terminal means with an ordinary electrically heated iron.

Fig; 2 1s a sectional view of one ty e of terminal plug, showing the manner of conmeeting the cord thereto.

Figs. 3, 4 and 5 are similar sections showig. 6 is a like section, showing the adaptation of theinvention to another form of conductor cord.

- The conductor cord which'is illustrated in Figs. 2 to 5, inclusive, is of that type known as reinforced portable cords, embracing two insulatedconductors 10-10 which are embedded in an insulating body "11', the whole .b ing preferably wrapped;

.bya .tape or braid 12.

14 designates a plug which may belof any approved type and by which the cord may be connected to a a sad iron 15.; vbaid plug, asfshown in Figs. 2, 3', 4 and 6."'inclusive, comprises a base 16 and a cap portion 17, the base 16 having #11 upstanding central member 1 8jwl1icl exof Cook and State b construction.

gripping salients 21,

the base 16 is threaded of spaced gripping points or relied upon it .sure and resultingacute pinching of'the portable electrical device, as

able kink orbend stresses this portion of the tends intothe cap and between which member 18 and the wall of the cap'the separate conductors 10 of the cord are gripped. Said ase is screw threaded to the cap or body portion 17 so as to move the gripping surfaces of the upstanding part 18 toward and from other gripping surfaces on the interior wall, of the cap or body 17. The insulating body 11 of the cord is stripped from the conductors within the receptacle or plug 14,

and the pair of wires are stripped at their terminals for connection with the usual binder screwssl9 which are threaded into the base. Said screws serve also as a means to connect the terminal pins 20 to the base of the well known two-pinfattachment plug It will be understood, however, that the plug may have any other de; sired form of terminal connection- In accordance with one phase of my invention the upstanding member 18 of the base and the inner wall of the cap 17 are provided with a series of vertically spaced 22, respectively. The salients on one of the members preferably lie opposite to the spaces between the salients of. the other member so that said salients are out of line or staggered-relatively to each other. The-said salients preferably extend continuously around the members bearing them.

As herein shown, the salients are by a number of stepped shoulders members, but may be of'other form. When into the cap to an formed on said.

extent to effect a gripping action/on the parate conductors 1.0 2 said salients are spaced apart a distance less than the diameters of the conductors, so as to pinch into' results in a plurality of pointsspaced along the lengths of uctors and, by reason conductor, is such astoplace an objectionin the wire; -and when said wire is subjected ,to frequentzpulling wire soon b eaks, With the cb struction describe t baselines of the number 95. the' insulating covers of the conductors.

- plug'or receptacle, but'this is accomplished the outlet, so that the firmest binding stress on the conductors is that nearest the bmdln'g v the wire, so as to be utlhzed to transmit pullwit out in any way injuring the wire. De-

sirably, and in practice the salients closest, adjacent to the binding screws 19 are more closely spaced than those near the neck of screws. v

Another phase 9f the invention resides'in reinforcing the cord at the plugs in such a way as to prevent it sharply bending over the edge 24 of the plug, where. the cord emerges from the plug, and thus avoiding the tendency of breaking the cord due to such sharp bending when a pulling stress is exerted on the cord at an angle to the axis of the plug, y

This latter phase of the invention contemplates the .use of a reinforcin medium (Figs. 2, 3, 4 and 5) of some flexibility and resiliency as a metal wire. It .may be a round wire, as shown in Fig. 2, or a flat, twisted wire, as shown in Fig. 4. 1 This reinforcing medium lies between the conductors 10 and may be embedded in the cord during the formation of the latter. The. reinforcing medium extends well into the plug or receptacle 14 and the upstanding socket 26 to receive-the end of the wire, when the constructions shown in Figs. 2 and 4 are followed whereby the wire is anchored to the plug. It will be obvious that the presence of the wire or other reinforcing medium 25 in the cord allows the cord-to take a gradual curve over the margin'24, as shown in dotted lines in Fig.. 2, and that it will avoid sharp bending of thecord. about the margin of the plug or receptacle when a pulling stress is applied to the cord'in a direction at an angle to the axis of said plug.

In the constructlon shown in Fig. 3 the reinforcing wire or rod 28 takes the form of a pin, which is inserted into the cord after the latter is formed. In order to readily insert this pin into the completed cord, a soft core may be molded in the cord in the place occupied by the wire 25, in the construction shown in Figs. 1 and 4, this core being soft enough to permit the wire or pin to be inserted in place. In the construction shown in Figs. 3 and 5 the base 16 is provided with a downwardly opening axial recess 29 through which the pin or wire 28 may be inserted. Said pin or wire is headed and a spot 30 of wax, solder or like material wire or pin in place.'

In the construction shown in Fig. 4the plug is modified so as to include the members of a splitor two part, coned gripping sleeve 31, the conical ends of which coact with internal coned 0r tapered surfaces 32 of the extended neck 33 of the plug, The purin said recess holds the headed end of the pose of the separable gripping sleeve 31 is v to bind the tape or braid 12 against the cord so as to avoid stripping of the braid therefrom. 4

In Fig. 5 the reinforcin wire 35, which revents sharp bending of the cord 36, is mtended to extend throughout the cord length and is adapted to be headed at both plugs, as by a nut threaded to the end' of ing stress on the cord to the plug, and therebyavoid transmittmg to the binding screws stresses due to pulls exerted on the cord. In

this construction, therefore, the salients may be omitted from the cap 37 and base 38. Moreover, the Wire 35 may be .barbed, as shown, to effect a more re iable union between the wire and cord envelop.

In Fig. 6 is illustrated the application of my improved cord fastening device to an ordinary two conductor twisted cord. In

this construction the gripping salients 21,

22, between which the conductors 39 of the cord are gripped may have the same form as in the construction shown in Figs. 2, 3 and 4, and the parts, therefore, bear like reference characters. 1

It will be understood that the invention herein disclosed may be adapted in other specific embodiments, structurally differing from those herein shown, and that the invention is not, therefore, limited to the structuresshown, except as such structures are hereinafter made the subject of specific comprising a terminal receptacle embracing two members of insulating material between which the conductors of the cord are adapted to be confined, said members being provided with opposing gripping salients spaced longitudinally of said cord, with means to force said members together on the cord, said salients being of variable graduated distances apart. I

3. Attachment plugs for electrical devices comprising a terminal receptacle embracing two members between which the conductors of the cord are adapted to be confined, said members being provided with a series of gripping salients spaced longitudinally of said conductors, with means to force one of 4. Attachment plugs for electrical devices comprising a plug embracing a cap and a base threaded thereto and having an upstanding member extending into the cap, said upstanding member and wall of the cap being provided with a series of longitudinally spaced conductor gripping salients.

5. Attachment plugs for electrical devices comprising a termlnal receptacle embracing two members between which the conductors of the cord are adapted to be confined, said members being provided with a series of gripping salients spaced longitudinally of' said conductors, with means to force one of said members toward the other, binder elements for the conductors, and the gripping salients nearest adjacent to said binder elements spaced more, closely than -the other gripping salients.

6. Attachment plugs for electrical devices comprising, in combination with a conductor cord, a terminal receptacle embracing two members between WhlCh the conductors of the .cord are confined, said members being provided with a series of gripping salients spaced longitudinally of said conductors, with means to force one of said members toward the other, said cord being provided with a central reinforcing medium to avoid sharp bending of the cord about the edge of the receptacle.

7. Attachment plugs for electrical devices comprising, in combination with a conductor cord, a terminal receptacle embracing two members between which the conductors of the cord are confined, said members being provided with a series of gripping salients spacedv longitudinally of said .conductors, with means to force one of said members toward the other, said cord comprising a plurality of conductors embedded 'ce'mber, 1917.

in a body of pliable insunnai, and a reinforcing medium extending centrally through said body.

8. In combination with a conductor cord,

and a terminal receptacle comprising two members between which the cords of the conductor are confined, of a reinforcing member embeddedin the cord at said receptacle and extending beyond the receptacle, and means to anchor said reinforcing member to said. receptacle 9. Attachment plugs for electrical devices comprising two members between which the cords of the conductor are adapted to be confined, said members each having a series of axially spaced salients to directly engage the conductors with the salients of one member offset relatively to those of the other member.

10. Attachment plugs for electrical devices comprising two members between which the cords of the conductor are adapted to be confined, each member having a plurality of axially s aced salients to directly engage the con uctors, the said salients being formed on gradually enlarging parts of the members.

11. Attachment plugs for electrical devices comprising two members between which the cords of the conductor are adapted to be confined, each member having a series of axially spaced salients to directly engage the conductors, the said salients being of different diameters along the series.

In testimony whereof I claim' the foregoing as my invention, I hereunto append my signature in the presence of two witnesses at Chicago, Illinois, this 22nd day of De- BERTRAM J GRIGSlBY. 

